Sewing machine



July 14, 1931.

A. B. FOWLER 1,814,550

SEWING MACHINE Filed June 11, 1926 3 Sheets-Sheet l I A. B. FOWLER July 14, 1931.

SEWING MACHINE Filed June 11, 1926 3 Sheets-Sheet 2 July 14, 1931. A. B. FOWLER 1,814,550

SEWING MACHINE Filed June 11,1926 3 Sheets-Sheet 3 15L fl 5. FZw/e/f, deceased,

- necessary 3 will'b'e readily'understood by those Patented July 14, 1931 B. FOWLER, DECEASED; LATE OF BEVEBLY.MASSACHUSETTS, BY MARY IF.

FOWLER, ADMINISTRATRIX, F BEVERLY, MASSACIIU$ETTS, ASSIGNOR TO UNETED SHOE MACHINERY GORPORATION,-OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY SEWING MACHINE Application filed .l'une 11, 1926. Serial No. 115,201.

The present invention relates to hook needle lockstitch sewing machines, and more particularly to needle thread handling devices adapted for use insuch machines.

I The object of the invention is to provide a novel and improved mechanism' for supplying needle thread for the stitch forming operation, and forsetting the stitch.

It is desirable in a loc'kstitch' machine, to set the stitch'a'gainsta yielding resistance. Difliculty has beenexperienced, however, notably'in cases where it hasbeen attempted tosetthestitch against a thread-tension, in obtaininga regular, even stitch, because of the tendency of the tension device to give upan excessive amount of thread or to overthrow. In order to eliminate this irregularit'y'in the sewing, the stitch is usually set against a thread lock, the amountof' thread forea'ch succeeding stitch being carefully measured out in advance.

One feature of "the present invention contemplates settingi'the' stitch against a yielding resistance, w1thoutat the sametime allowing any new thread to be drawn from the supply; so that anyposs'ibility of overthrow with the. resulting irregularity in the stitch is' eliminated.

More specifically, in the present embodie ment of the invention, the stitch is set against'thepull-o'fi lever which is arranged toyie'ld against the tension of a light spring,

while a relatively'heavy thread tension prevents any additional thread from being drawn from thesupply.

Another featu'reo'f the invention contemplates utilizing the yielding movement of the pull-off'leve'r'produced by the setting of the stitch as a means for measuring automatically the varying amou 't of thread to bepulledfro'm the supply as the work varies inthickness. v v

Thesevera'l features of the present invention' and the advantages attained thereby skilled in the art. from the following description taken in connection with the" accompanying drawings in which' Fig. 1 is'a side eleva tion of a McKay lockstitch' horn sewing machine illustrating one embodiment" of the present invention. Fig. 2 is a detailed front eievation,-part1y in section, showing the pulloff, take-up and thread lock. Fig.3 is a detailed side elevation, partly in section, of the parts shown in Fig. 2 with. their actuating mechanisms Fig. 4 is a side elevation showing somewhat diagrammatically the position of the needle thread and the thread handling mechanisms as the stitch is being set. Fig. 5 is asimilar viewof the parts illustrated in Fig. 4 after the pulloif has operated to'draw new thread from the supply, and the take-up has drawn the needle loop from the shuttle partially down through the work. e

Except as hereinafter described, the machine illustrated in the drawings is the same in construction and mode. of operation as the lockstitch McKay shoe sewing machine illustrated and described in the inventors application filed of even date herewith Ser ial No. 115,202. The machine is provided with a rotatable work supporting horn, a straight hookneedle, a loop taker in the form of a hook for passing the loops drawn up through the work by the needle over a bobbin case containing the locking thread and pull-oif and take-up mechanisms for handling the needle thread.

Referring more specifically to the drawings, the horn is'indicated at 6, the straight hook needle at8, the loop taker or hook at 10, a bobbin case loosely mounted within holdersin the machine frame at 12, a presser foot at 14, and an awl which acts also to feed the work at 16. The machine is driven from a belt pulley 18 through a two speed clutch and driving mechanism similar to that described in the Letters Patent to Richardson No. 885,378, and controlled from the foot pedal 20.

The needle thread handling mechanism which is more particularly the subject matter of the present invention, includes a takeup which acts to pull the needle loop from the shuttle partially back through the work, and a pull-oif mechanism whichalso forms a yielding resistance against which the'stitch is set by the loop taker or hook; A thread lock'is interposed between the takeup and pull-off to cooperate with these devices and a thread tension controls the feed ing of the thread from the supply to the pull-off.

The take-up mechanism comprises a take: up lever 22 carrying the two guide rolls 24 and 26 and pivotally mounted at its lower end on the shaft 28 rigidly held in the machine frame. The actuating connections for the lever 22 include the cam slide 30 and a link 32 adjustably connected to the lever through the pin and slot 34. Cooperating with the guide rolls 24 and 26 on the movable lever 22 is the guide roll 36 mounted on the fixed bracket 38 and the guide roll 40 mounted on the adjusting lever 42 which is fastened at its lower end to the rock shaft 44. The function of the adjusting lever 42 is to vary the action of the take-up in accordance with the thickness of the work to leave always the same amount of thread above the work and reduce to a minimum the amount which must be pulled around through the work by the retracting needle. The position of this lever is controlled from the presser foot bar through connections which include the lever arm 46 fastened to the rock shaft 44, connecting link 48, lever 50, link 52 and lever 54.

The thread lock which is provided to co operate with the take-up and pull-off mechanisms comprises a spring pressed plunger 56 mounted in a block '58 on a bracket 60 on the machine and equipped with a rough bearing surface against which the'thread is pressed by the locking action of a lever 62 which carries a similar surface oppositely placed. The thread locking lever 62 is pivotally mounted on the shaft 28 and is actuated by the cam slide 64 through the con necting link 66. The thread is guided from the thread lock to the takeup rolls by means of two guiding arms one indicated at 68 being formed on the block 58 and the other indicated at 70 being bolted to the bracket 60.

The pull-off mechanism comprises a pulloff lever 72, pivoted at 74 and carrying at its lower end the roll 76 which moves be tween the stationary rolls 78 and 80 pivotal.- ly mounted on an arm 82 of the bracket 60. The pull-oif lever has formed on itshub a small lever arm 84 which carries a roll 86 adapted to engage a projection or cam sur' face 88 on the hub of the take-up lever 22. As the take-up lever is turned by the action of the cam slide 30 to take up the preceding needle loop, the projection or cam 88 is brought into contact with the roll 86 andthe pull-off lever is turned about its pivot to draw new thread through the thread tension 90 from the supply. 7

In order that the stitch maybe set against a yielding resistance, a spring 92 is inserted between a pin 94 on the pull-off lever 72 and a thumb-screw 96 journalled in a plate 98 fastened to the bracket 60 so that thread will be drawn from the pull-off mechanism against the pressure of the spring in setting the stitch. The force exerted by the spring 92 is relatively smaller than the resistance in the thread tension so that the stitch is yielding resistance pull-elf mechanism ust de- ClTflWlD more thread from supply during the stitch setting operation,

the amount by which the pull-off lever 72 is pulled down against the tension of its spring 92 and consequently the effective throw of the lever in pulling off thread for the next stitch must vary in accordance with the thickness of the work. r

In the operation of the machine, as the needle retracts through the work the thread remaining in the preceding loop is drawn around through the work and an approximately equal amount is given up by the takeup mechanism. The loop is then taken from the needle over the bobbin-case by the loop taking hook, additional thread being supplied from the pull-off mechanism against the tension of spring '92. N 0 thread is permitted to'escape through the relatively heavy thread tension 90 so that the stitch is set entirely against the yielding resistance supplied by the spring 92. The position of the pull-oil lever 72 is thus finally determined in accordance with the thickness of the work before the thread lock is closed preparatory to drawing off more thread from the supply, the parts at this point in the operation being as illustrated in Fig. 4 of the drawings. The thread lock is now closed and the take-up lever 22 caused to turn about its pivot to draw the loop from the hook 10 par; tially down through'the work. At the same time, the projection or cam surface 88 on the hub of the take-up lever is brought into contact with the roll 86 to, turn the pull-off lever 72 about its pivot and draw new thread through the thread tension 90 from the supply. Fig. 5 of the drawings illustrates diagrammatically the position of the parts at the completion of this phase in the cycle of operations.

The nature and scope of the present invention having been indicated and the preferred embodiment of the invention having been specifically described, what is claimed is:

l. A hook needle lockstitch sewing machine having, in combination, stitch forming devices, a pull-01f mechanism which forms also a yielding resistance against which the stitch is set, a stitch setting device, and means for preventing thread from being pulled from the supply during the operation of the stitch setting device.

-2. A lockstitch sewing machine having, in

combination, stitch forming and setting devices including a hook needle, a take-up acting to pull the needle loop from the loop taker partially back through the work, a loop taker acting to set the stitch, a pullotf which forms a yielding resistance against which the stitch is set, a thread lock interposed between the pull-ofl and take-up, and a thread tension to prevent thread from being pulled from the supply during the operation of the stitch setting devices.

3. A hook needle lockstitch sewing machine having, in combination, stitch forming devices, a stitch setting device, a pull-off forming a yielding resistance against which the stitch is set, the amount of thread pulled off for the next succeeding stitch being governed in accordance with the thickness of the work by the extent of the yield, and a thread tension.

4. A lockstitch sewing machine having, in

combination, stitch forming devices including a hook needle acting during its retraction to draw thread from the preceding needle loop, a stitch setting device, a pull-0H including a yielding member against which the stitch is set, the amount of thread for the next succeeding stitch being governed in accordance with the thickness of the work by the final position of the yielding member, and means for preventing thread from being pulled from the thread supply during the operation of the stitch setting device.

5. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a take-up acting to pull the needle loop from the loop taker partially back through the work, a loop taker acting to set the stitch, a pull-01f forming a yielding resistance against which the stitch is set and acting thereafter to pull ofi for the next succeeding stitch an amount of thread governed in accordance with the thickness of the work by the extent of the yield, a thread lock interposed between the take-up and pull-0H, and a thread tension acting to prevent thread from being drawn from the supply during the operation of the stitch setting device.

6. A lockstitch sewing machine having, in v combination, stitch forming and settingdevices including a hook needle and a looptaker acting to pull thread from the preceding needle loop and set the stitch of which said preceding needle loop forms a part, a member against which the stitch is set arranged to yield while the stitch is being set, and means for preventing thread from being pulled from the supply during the entire stitch setting operation.

In testimony whereof I have signed my name to this specification.

. ,MARY F. FOWLER, Admimstmtriw of the Estate of Alfred B.

Fowler, Deceased. 

